Problem: Omar did 29 fewer jumping jacks than Vanessa in the evening. Vanessa did 50 jumping jacks. How many jumping jacks did Omar do?
Answer: Vanessa did 50 jumping jacks, and Omar did 29 fewer than that, so find the difference. The difference is $50 - 29$ jumping jacks. She did $50 - 29 = 21$ jumping jacks.